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.\" $FreeBSD: src/lib/libc/sys/aio_return.2,v 1.17 2003/01/13 10:37:11 tjr Exp $
.\"
.Dd September 26, 2008
.Dt AIO_RETURN 2
.Os
.Sh NAME
.Nm aio_return
.Nd retrieve return status of asynchronous I/O operation (REALTIME)
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In aio.h
.Ft ssize_t
.Fo aio_return
.Fa "struct aiocb *aiocbp"
.Fc
.Sh DESCRIPTION
The
.Fn aio_return
system call returns the final status of the asynchronous I/O request
associated with the structure pointed to by
.Fa aiocbp .
.Pp
The
.Fn aio_return
system call
should only be called once, to obtain the final status of an asynchronous
I/O operation (once
.Xr aio_error 2
returns something other than
.Er EINPROGRESS) and to clean up system resources.
However, if
.Fn aio_return
is not called at all,
.Xr aio 4
will leak resources.
.Sh RETURN VALUES
If the asynchronous I/O request has completed,
the status is returned as described in
.Xr read 2 ,
.Xr write 2 ,
or
.Xr fsync 2 .
On failure,
.Fn aio_return
returns
.Dv -1
and sets
.Dv errno
to indicate the error condition.
.Sh ERRORS
The
.Fn aio_return
system call will fail if:
.Bl -tag -width Er
.\" ==========
.It Bq Er EINVAL
The
.Fa aiocbp
argument
does not reference an outstanding asynchronous I/O request.
.\" ==========
.It Bq Er EINPROGRESS
The asynchronous I/O request is still in progress.
.El
.Sh LEGACY SYNOPSIS
.Fd #include <aio.h>
.Pp
.Ft int
.br
.Fo aio_return
.Fa "struct aiocb *aiocbp"
.Fc ;
.Pp
The type of the return value has changed.
.Sh SEE ALSO
.Xr aio_cancel 2 ,
.Xr aio_error 2 ,
.Xr aio_suspend 2 ,
.Xr aio_write 2 ,
.Xr fsync 2 ,
.Xr read 2 ,
.Xr write 2 ,
.Xr aio 4 ,
.Xr compat 5
.Sh STANDARDS
The
.Fn aio_return
system call
is expected to conform to the
.St -p1003.1
standard.
.Sh HISTORY
The
.Fn aio_return
system call first appeared in
.Fx 3.0 .
.Sh AUTHORS
This
manual page was written by
.An Wes Peters Aq wes@softweyr.com .
